<form>
  <div class="form-group">
    <input type="text" class="form-control" placeholder="Recipients">
  </div>
  <div class="form-group">
    <input type="text" class="form-control" placeholder="Subject">
  </div>
  <div class="form-group">
    <textarea class="form-control" placeholder="Message"></textarea>
  </div>
  <button type="submit" class="btn btn-success">Send</button>
</form>